This invention relates to plasma arc furnaces and the production from waste material ionized and disassociated in the furnaces of synthesis gasses and stable inert materials that can be re-cycled or safely placed in landfills, and more particularly to a way of feeding waste matter into such a plasma arc furnace to assure complete ionization and disassociation of the waste matter, and to entrap hazardous or otherwise problem waste materials so that they do not inadvertently escape ionization and disassociation in the furnace.
The pollution of our environment is a problem that must be addressed with equipment that is capable of recycling waste material and producing high value products, thereby gaining the social acceptance and generating the income necessary to offset the acquisition and operating costs of the equipment. Such equipment must also be capable of processing very large quantities of waste material in a relatively short period of time, simply and reliably with minimal emissions. Otherwise such equipment will not be accepted nor find the wide spread application and use necessary to significantly improve environmental conditions.
The safe treatment and disposal of all waste materials is demanded in most developed nations. In this regard, there is a growing demand on industry by environmentalists and government agencies to alleviate potentially toxic and/or contaminated waste disposal sites that were employed for many years prior to the public""s heightened environmental concerns and the enactment of environmental legislation.
The daily generation of solid wastes is a fact of life in industrialized society and their disposal is becoming an ever-increasing problem. The more common of these waste materials is Municipal Solid Waste (MSW). Disposal of MSW through landfill is becoming increasingly less attractive and more difficult as sites are becoming full, alternate sites are becoming scarce and the knowledge and reality of contamination of groundwater, adjacent facilities and property are becoming more prevalent and disconcerting. In the search for more efficient and less costly disposal, Energy From Waste (EFW) technologies are being developed which also create energy as a byproduct of the destruction process. The most widely known type of EFW facility is incineration in various forms; however, incinerator EFW system require extensive air pollution control systems to reduce emissions below regulatory levels and they also produce toxic flyashes. EFW systems based on the gasification process have more inherent promise for lower emission of all environmental contaminants through both a cleaner and a lower volume of product gas, and a cleaner solid residue.
The combustion of waste materials to reduce their volume or release heat energy is one of the single greatest causes of air pollution. Such waste materials include municipal solid waste (MSW), industrial or household waste chemicals, chemical weapons, medical waste, infectious or otherwise biologically hazardous materials, human or animal sewerage, soils or marine sediments excavated or dredged from contaminated sites, recovered waste material excavated from landfills, used tires, or used oil filters as well as vegetable or petroleum based oils, oil bearing shale and high sulfur coal.
Finally, waste material that is processed using energy from waste technology that include plasma arc furnaces too often do not completely recover the processed material as byproducts in biologically and ecologically safe forms because the material is not completely ionized and disassociated.
Thus, there is a need in the art for improved apparatus to dispose of waste materials, including MSW, in a cost effective way that will ameliorate the present problems with waste disposal.
There is also a need in the art for improved apparatus to dispose of waste materials, including MSW, that can yield environmentally safe materials that can be recycled into useful products or are safe in landfills.
There is also a need in the art for improved apparatus to dispose of waste materials, including MSW, that can produce byproducts useful to produce electrical energy that can be used to drive the process, and even to be sold and make a profit from using the process.
There is also a need for improved apparatus for completely ionizing and disassociating waste material to eliminate the escape of any biologically and ecologically unsafe materials.
The foregoing needs in the prior art are met by the present invention. Apparatus is disclosed that utilizes a high temperature plasma arc furnace operating under fast pyrolysis conditions to process many kinds of solid and liquid waste, including municipal solid waste, and produce synthesis gas and inert matter therefrom. This extracts the potential energy value within waste matter without combustion of the matter. Most importantly, the waste matter being processed is fed into the furnace in a way that assures that no biologically and ecologically unsafe materials or byproducts escape the process and are released to the atmosphere.
The synthesis gases produced, which are mainly carbon monoxide (CO) and hydrogen, are then used to produce electricity using molten carbonate fuel cells. The electricity generated is enough to power the plasma arc furnace and there is a surplus that can be sold.
Alternatively, the synthesis gas can safely be used to power a gas turbine or internal combustion reciprocating engine without melting the turbines blades or the valves and piston crowns of an internal combustion engine through the introduction of de-ionized water vapor at their fuel inlets.
Other gasses that may be produced in the process can be separated, collected and re-cycled for use.
Most importantly, the waste matter being processed is fed into a molten bath in the furnace through hollow electrodes that produce the plasma arc in a way that assures that no biologically and ecologically unsafe materials or byproducts escape the ionization and disassociation process and are inadvertently released to the atmosphere.
Hazardous elements remaining in the plasma arc furnace that cannot otherwise be recycled in a safe manner, and non-hazardous materials remaining in the plasma arc furnace, are all entrapped within a silica/ceramic material that is tapped off the furnace to produce a geologically stable, leach proof media capable of being recycled into high value construction or building materials and components. Alternatively, the stable, inert, leach proof media from the plasma arc furnace may safely be placed in landfills.